<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <style>
        /* div::after{
            content: ""
        }
        div::before{
            content: "小"
        } */
        div{
            width: 100px;
            height: 100px;
            border: 1px solid #000
        }
        div::first-letter{
            color: green;
            font-size: 30px;
        }
        div::first-line{
            color: green
        }
    </style>
</head>
<body>
    <div>强哥强哥强哥强哥强哥强哥强哥强哥强哥强哥强哥强哥强哥强哥强哥</div>
</body>
</html>
<!-- 
    伪对象的使用方式:块级元素
        - ::after{content:''} 在xx之后添加
        - ::before{content:''} 在xx之前添加
        - ::first-letter 定义对象内第一个字符的样式
        - ::first-line:定义对象内第一行的样式
 -->